2L Gen3 Smart Relay
Two no-neutral lighting circuits from one module, made for light switches that have no neutral in the switch box.
Filter guide
What's a channel?
One channel switches one circuit. A 2-channel relay behind a single plate can run two lights on their own schedules, or a light and an exhaust fan, without needing a second device.
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One channel
Switches one circuitSwitches one thing on its own: a light, a fan, an exhaust.
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Two channels
Switches two circuitsTwo circuits controlled separately, like both halves of a double switch.
Selected
Everything you need to know
The sections below cover what this relay can do, the jobs people put it on, the full specifications, and how warranty and returns work. If something's still unanswered, the questions at the bottom cover the common ones.
Product features
Works without a neutral wire
Plenty of Australian light switches have no neutral in the switch box, which rules out most smart switches unless an electrician rewires the circuit. The L series is built for exactly that wiring: it powers itself through the load instead. With very low-wattage LED lighting, add the Shelly Bypass to keep it stable.
Your wall switches keep working
A Shelly relay sits behind the switch plate, in the wall box with the wiring you already have. The switch stays connected and keeps doing its job, and the relay adds app control, schedules and automations alongside it. Nobody in the house has to learn anything new, and if your internet drops out, the switch on the wall still works.
Automations that don't need the internet
Schedules, timers and scenes run on the relay itself, not on a server overseas. Set lights for sunset, a towel rail for weekday mornings, or a fan to run down after the bathroom light goes off, and it all keeps working through an internet outage. There's no subscription, and the embedded web interface gives you full control from a browser on your own network.
What is a Shelly relay?
A relay is a switch you never see. It wires into the circuit between the supply and the light or appliance, so that circuit can be switched from the wall, from your phone, from a schedule or from an automation. The switch already on the wall stays wired in and keeps working for anyone who just wants to flick it.
One channel per circuit
Channels decide how many you buy. The range runs from one to four, so a single light takes a one-channel module and a plate driving two circuits takes a two-channel. Each channel switches its circuit independently.
Wall box or switchboard
The smaller modules sit in the wall box behind an existing switch, where the constraint is the space left behind the mechanism. Pro units clip onto DIN rail in the switchboard instead, which is where whole circuits and three-phase work belong.
What PM on the end means
A PM model measures the load it is switching and reports power and accumulated energy alongside the on-off state. Models without it switch only. The specifications on this page tell you which one you are looking at.
It runs without the internet
Schedules and scenes are stored on the relay and run there, so the light still comes on at dusk when your connection is out. Every unit serves its own web interface on your network with no account, and Shelly publishes its local API, which is why Home Assistant ships an official integration.
One circuit at a time The usual start
Most people begin with a single module behind the switch they use most, often the lounge or the outside light. The plate and the wiring stay as they are, and that one circuit becomes something you can schedule or run from your phone. Add the next one whenever you feel like it.
The whole switchboard at once Or start at the board
When the board is already open for a rewire, a new build or a switchboard upgrade, Pro units on DIN rail cover several circuits from one place. They run the same firmware and the same app as the in-wall modules, so a house can mix the two freely.
Nothing has to be settled up front. Each relay works on its own, there is no hub to buy first, and you can start with one circuit and go as far as you like from there.
Works with
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Pairs with Amazon Alexa
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Pairs with Google Home
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Pairs with Home Assistant
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Pairs with SmartThings
Joins your home network; control from the app, no hub or bridge needed.
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Wi-Fi
Used once, to get it onto your Wi-Fi.
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Bluetooth
Works offline
Runs on your home network. Only remote access needs the internet.
Which relay do I need?
Gen3 is the value pick and does everything most homes need. Gen4 adds Zigbee and Wi-Fi 6, and Matter is on out of the box, so it joins Apple Home or a Zigbee network with no hub in between. Pro is DIN rail hardware for the switchboard.
If you run the Shelly app or Home Assistant over Wi-Fi and just want a reliable relay behind a switch, save the money and buy Gen3. Pay the difference for Gen4 if Matter or Zigbee matters to your setup. One thing to know: Zigbee on Gen4 is an either/or mode, so a relay switched to Zigbee leaves Wi-Fi entirely. And if you're searching for Gen2, it shipped under different names: the Plus and Pro ranges.
| Feature | Gen3 This model | Gen4 | Pro |
|---|---|---|---|
| Best for | Everyday Wi-Fi setups on a budget | New setups and Matter or Zigbee homes | Switchboards and bigger jobs |
| Connects over | |||
| Matter | On some models, turned on in settings | Built in and on by default | Not supported |
| Mounting | Behind the switch or power point | Behind the switch or power point | DIN rail in the switchboard |
| Price from | $24.95 | $34.95 | $89.95 |
| Model | Channels | Price |
|---|---|---|
| 1L Gen3 Smart Relay | 1 channel | $59.95 |
| 2L Gen3 Smart RelayViewing | 2 channels | $64.95 |
Behind the switch
Fits in the wall cavity behind an existing switch or power point. The switch on the wall stays and still works; the relay sits behind it and makes the circuit smart.
In the switchboard
Clips onto the standard rail in your switchboard, next to the circuit breakers. Keeps everything in one serviceable spot, which suits whole-home installs and bigger jobs.
What's a channel?
One channel switches one circuit. A 2-channel relay behind a single plate can run two lights on their own schedules, or a light and an exhaust fan, without needing a second device.
Specifications
No specifications match.
- Type
- Module
- Module size
- Standard
- Channels
- 2 channels Also available: 1
- Form
- In-wall
- Housing material
- Plastic
- Power
- Hardwired
- Supply voltage
- 220–240 V
- Standby power
- 1.2 W
- Generation
- Gen3
- Neutral required
- No
- Shelly Bypass included
- Yes
- Neutral not needed
- Yes (Shelly Bypass is required for the load at O1)
- Min. load without neutral and without a Bypass
- No (Shelly Bypass for 1L/2L is required for the load at O1), for all LED lights. No, Bypass is not needed for incandescent lights.
- Dry-contact mode
- No
- Energy monitoring
- No
- Drives blinds & shutters
- No
- Local control
- Yes
- Standard
- 802.11 b/g/n
- Range (indoors)
- 30 metres
- Version
- 4.2
- Range (indoors)
- 10 metres
- RF band
- 2400 - 2483.5 MHz
- Max. RF power
- < 4 dBm
- Operating temperature
- -20–40 °C
- Operating humidity
- 30–70 % RH
- Max altitude
- 2000 metres
- Size (HxWxD)
- 37x42x16 ±0.5 mm / 1.46x1.65x0.63 ±0.02 in
- Weight
- 28 g / 1 oz
- Screw terminals max torque
- 0.4 Nm / 3.5 lbin
- Conductor cross section
- 0.5 to 4 mm² / 20 to 11 AWG (solid, stranded, and bootlace ferrules)
- Conductor stripped length
- 6 to 7 mm / 0.24 to 0.24 in
- Mounting
- In-wall
- Shell color
- Cyan
- Terminal color
- Black
- Storage temperature
- 10°C to 40 °C
- Max. switching voltage
- 240 V~
- Max. switching power
- * 200 W through O1 * 700 W through O2
- Internal-temperature sensor
- Yes
- Protocol
- 802.11 b/g/n
- RF band
- 2401 - 2495 МHz
- Max. RF power
- < 20 dBm
- Range
- Up to 30 m / 100 ft indoors and 50 m / 160 ft outdoors (Depends on local conditions)
- CPU
- ESP-Shelly-C38F
- Clock frequency
- 160 Mhz
- RAM
- 512 KB
- Flash
- 8 MB
- Schedules
- 20
- Webhooks (URL actions)
- 20 with 5 URLs per hook
- Scripting
- Yes
- MQTT
- Yes
Use cases
Outdoor lights on at sunset, off at midnight
Porch, path and garden lighting follows the sun through the year without you touching a thing. It also makes the house look lived-in while you're away.
A bathroom fan that runs itself
The exhaust fan keeps running after the light goes off, long enough to clear the steam, then shuts itself down. Add a humidity sensor and it only runs when the room needs it.
A warm towel rail on winter mornings
Schedule the rail for weekday mornings and it's warm when you step out of the shower, off again before you leave. No more discovering it's been heating an empty house all day.
Common questions
Quick answers before you buy. We test this gear ourselves. Can't find yours? Ask our Melbourne team
Yes. Shelly relays wire into 240V mains circuits, and in Australia that work must be done by a licensed electrician. A single relay is a quick job.
No. The L series powers itself through the load, so it suits the many Australian light switches that have no neutral in the switch box. With very low-wattage LED lighting, add the Shelly Bypass to keep it stable.
No. It connects to your Wi-Fi and works from the Shelly app with no hub and no subscription. Schedules and automations run on the device itself, so they keep working if the internet drops out.